Organic light-emitting diodes (OLEDs) are recognized as a next-generation display and/or lighting technology. Due to the 3:1 triplet to singlet exciton issue, development of emitting materials for OLED application maybe mainly focused on phosphorescent materials. Among phosphorescent materials, metal organic materials containing heavy transition metals may exhibit desirable performance in OLED application. Iridium is a commonly used heavy transition metal while platinum is an up-and-coming candidate. Devices fabricated from iridium- and platinum-based materials have good device performance for mass production.
However, prices for iridium- and platinum-based materials may be relatively high. There is a desire to reduce costs for emitting materials. Zinc-based materials may provide an advantage related to cost, for example. Nevertheless, efficiency and/or stability of devices fabricated from zinc-based materials may be questionable.